There are many challenges facing the aerospace industry that can be addressed with new concepts, technologies, and materials. However, current design methods make it difficult to include these new ideas early in the design of aircraft. This is especially true in the structures discipline, which often uses weight-based methods based upon statistical regressions of historical data. A way to address this is to use physics-based structural analysis and design to create more detailed structural data. Thus, the overall research objective of this dissertation is to develop a physics-based structural analysis method to incorporate new concepts, technologies, and materials into the conceptual design phase. The design space of physics-based structural design problem is characterized as highly multimodal with numerous discontinuities; thus, a large number of alternatives must be explored. Current physics-based structural design methods tend to use high fidelity modeling and analysis tools that are computationally expensive. This dissertation proposes a modeling & simulation environment based on classical structural analysis methods. Using classical structural analysis will enable increased exploration of the design space by reducing the overall run time necessary to evaluate one alternative. The use of physics-based structural optimization using classical structural analysis is tested through experimentation. First the underlying hypotheses are tested in a canonical example by comparing different optimization algorithms ability to locate a global optimum identified through design space exploration. Then the proposed method is compared to a method based on higher fidelity finite element analysis as well as a method based on weight-based empirical data to validate the overall research objective.

In my senior project I work with the unseen furniture: the side table. The name, Quadro, is a combination of the italian word quattro that means four and the latin word ”quadratum” or ”quadratus.”  After conducting an analysis of different side tables, I concluded that the side table's function is primarily to elevate other artifacts. I draw connections to the creation of identity through consumption and have created a sidetble through combining furniture design and conceptual design. The project was finalized with a survey to see if identity is visible through the selection of artifacts. / I mitt projekt arbetar jag med den osedda möbeln: sidobordet. Namnet Quadro är en blandning mellan italienskans quattro som betyder fyra och latinets ”quadratum” eller ”quadratus”. Efter analys av olika sidobord kom jag fram till att sidobordets primärfunktion är att höja upp andra artefakter. Jag drar kopplingar till identitetsskapande genom konsumtion och har skapat ett sidobord genom att kombinera möbeldesign med konceptuell design. Projektet slutförs med en undersökning för att se om identitetsskapandet går att observera genom valet av artefakter.

Busca-se encontrar a solução de compromissos para o desenvolvimento de uma aeronave multifuncional, de aviação geral, a pistão, que atenda às necessidades do mercado brasileiro e cujas características de desempenho estejam próximas ou superiores às das aeronaves típicas da aviação geral que operam nos Estados Unidos e Brasil. O objetivo principal do trabalho consistiu em desenvolver uma metodologia para projetos conceituais de aeronaves de pequeno porte e de uma família de aeronaves de forma que a geradora da família possa ser facilmente convertida em configurações diferentes, conservando o maior número de partes em comum, mantendo as características de desempenho almejadas e cumprindo com os requisitos de certificação impostos para a categoria. Apresentam-se definições, conhecimentos e técnicas na área de projetos aeronáuticos e descrevem-se de forma sucinta os aspectos mais importantes que envolvem o projeto conceitual. Em seguida é exposta a metodologia utilizada e são definidos os objetivos e os compromissos. Finalmente são apresentadas tabelas geradas pelo software PCA-Projeto Conceitual de Aeronaves e gráficos contendo as caracterizações onde se enquadra o objeto de estudo, a discussão e as conclusões da investigação. / The purpose of this work is to derive compromise solutions for the conceptual design of a general aviation aircraft, aimed to fulfill the requirements of the brazilian market. Fitted with a conventional piston engine, such aircraft should however sport technical and flight characteristics which are equal or better than those found on existing typical general aviation aircraft in operation both in Brazil and United States. The main objective of the thesis consisted of development of methodology for the conceptual design of a family of light aircraft so that the \"core aircraft\" can be regarded as a platform for the derivation and conversion to any of the family members - two, four and six - seats. Commonality of parts to the highest degree possible, achievement of a set of performance and efficiency goals and compliance with the existing certification requirements for the aircraft category are some of the main project drivers. The work presents the major topics definitions, the main specific techniques required in the subject of aircraft conceptual design followed by the key aspects associated with such an undertaking. The employed methodology is presented next, followed by the set objectives and compromise solutions so reached. Finally, the results for the three aircraft family are presented both graphically and in a set of data tables complemented by a few print-outs of the computer screen outputs generated by the software developed - PCA, which embodies the whole work carried out and can be used for the further improvements in the future. The conclusions present some critical analysis points and suggestions for the future work.

Since the realisation of the computer, and shortly after the inception of artificial intelligence (AI), there has been an explosion of research solving human-level tasks using autonomous entities that are able to learn about an environment by observing and influencing it, known as intelligent agents (IA). This potent AI technique has yet to filter into the field of thermoscience, where the conceptual design and optimisation of complex energy systems has been a particularly challenging problem. Much of the design process still requires human expertise. But with the continual increase in computational power and the use of IAs, it is now time to shift the responsibility from the human to the computer. This research attempts to answer the question of whether it is possible for a computer to conceptually design a complex energy system autonomously, from inception. The complex energy system to be designed and optimised is a thermoacoustic heat engine (TAHE), which converts thermal to acoustic power. The complexity of its physical behaviour and its many design parameters makes it a challenging energy system for conceptual design and optimisation and consequently an ideal candidate for this particular research. The TAHE is designed for low temperature waste heat utilisation from a baking process. In this work an approach is employed that is based on a reinforcement learning intelligent agent (RLIA). The RLIA is first employed to simultaneously optimise thirteen design parameter values. The RLIA was able to learn key design features of a TAHE which lead to the reduction in acoustic losses and an acoustic power from the engine of 495.32 W, when the thermal power input was 19 kW. For the main experiment, the RLIA must conceptually design the TAHE from scratch, changing both the parameter values and the configuration of the device. The results have shown the remarkable ability of the RLIA to identify several key design features of the TAHE: the correct configuration of the device, selecting designs that reduce acoustic losses, create positive acoustic power in the stack region and determine the region of optimality of the design parameter values. The RLIA has shown a great capacity to learn, even when contending with a complex environment and a vast search space. With this work we have introduced RLIAs as a new way approach to such multidimensional problems in the field of thermoscience/thermal engineering.

O projeto de produtos e sistemas técnicos complexos requer a compreensão em nível de sistemas e subsistemas para formular soluções eficientes e integradas ao seu contexto. Para auxiliar esta compreensão, o conhecimento de projeto deve ser representado utilizando níveis adequados de abstração de acordo com a fase do projeto. A fase de projeto conceitual requer tipos de representação capazes de atingir um alto nível de abstração para a exploração de conceitos que conduzam a soluções criativas. O paradigma da orientação a objetos, que é fundamentado pela abstração, faz parte da engenharia de software, mas também pode ser aplicado para o projeto de artefatos físicos porque permite a representação dos elementos do mundo real através de uma linguagem simples, acessível e com alto nível de abstração. Ademais, o paradigma da orientação a objetos permite a reutilização do conhecimento de projeto devido à sua capacidade de estruturar a informação em um formato adequado para isto. O presente trabalho propõe um framework para representar o conhecimento de projeto de produto aplicando o paradigma da orientação a objeto. Inicialmente, foram identificados os elementos conceituais da tese e suas relações, para na sequência definir o modelo do framework e o seu método de aplicação O framework utiliza uma linguagem de representação diagramática que pode evoluir desde um mapa mental, com elementos diversificados e pouco ordenados, até uma rede estruturada de classes e relacionamentos em um modelo de classes. Um modelo de classes pode concentrar conhecimento sobre o projeto, servindo como uma estrutura geral que conecta e relaciona diferentes blocos de informação associados aos produtos e sistemas que estão sendo elaborados. A verificação da aplicabilidade do framework foi realizada por especialistas da área de design mediante o desenvolvimento de um projeto de produto em nível conceitual e do preenchimento de questionário de avaliação. / The design of complex technical products requires understanding at the system and subsystem level to formulate efficient and integrated solutions to their context. To support this understanding, the project knowledge can be represented using appropriate levels of abstraction according to the project phase. The conceptual design phase requires types of representation that reach a high level of abstraction for the exploration of concepts that lead to creative solutions. The object-oriented paradigm is based on abstraction and is part of software engineering, but can also be applied to the design of physical artifacts because it allows the representation of realworld elements through simple, accessible and in high-level abstraction language. In addition, the object orientation paradigm supports the reusability of project knowledge due to its capacity to structure the information in patterns. The present work proposes a framework to represent product design knowledge using the objectoriented paradigm First, the conceptual elements of the thesis and their relationships were identified, after; the framework model and their method of application were constructed. The framework uses a diagrammatic representation language in which a mental map, with diversified and unordered elements, can progress into a structured network of classes and relationships in a class model. A class model can focus knowledge about the project, serving as a general structure that connects and relates different blocks of information associated with the products and systems being developed. The verification of the applicability of the framework was carried out by specialists in the design area through the development of a product design at conceptual level and the answering an evaluation questionnaire.

This thesis develops a paradigm for conceptual design based on the idea that dimensional analysis can improve the evaluation and comparison of concepts of solution during the conceptual design process. The conceptual design approach developed in this research is a combination of tasks which starts with the identification of the customer needs in a formalized manner is followed by the generation of design concepts taking into account the different phases of the physical life cycle and ends by the evaluation and adequacy analysis of the concepts of solution with the formalized needs.<br /><br />The General Design Theory (GDT) is used as the methodological basis of this work. Using the results of GDT, the research introduces a definition of the concept of function which is generic and not dedicated to a solution-based approach. Consequently the concept of function fulfils its intended objective of modelling the design problems at a general level. In addition to the concept of function, this thesis introduces a series of classifications based on generic concepts and rules aimed at generating concepts of solutions progressively. All these concepts are integrated into the developed metamodel framework. The metamodel provides a group of generic concepts associated with laws and mapped with a normalized functional vocabulary. The metamodel framework is an intermediate structure developed in order to provide guidance during the synthesis process and to meet the initial condition in order to transform the classification structure into a metric space. A metric space is a topological space with a unique metric. The transformation of the initial topological space into a metric space can be obtained when a series of conditions are verified. The first condition consists of clustering the concepts of solutions in order to underline the comparable aspects in each of them. This is done by using a set of dedicated rules. In addition three other fundamental conditions should be obtained. The metamodel framework ensures the first condition; an enhanced fundamental system of unit provides the second condition and a paradigm of separation of concept the third one. When all these three conditions are verified, it becomes possible to transform the design problems modelled by four types of generic variables into a series of dimensionless groups. This transformation process is achieved by using the Vashy-Buckingham theorem and the Butterfield's paradigm. The Butterfield's paradigm is used in order to select the minimum set of repeated variables which ensure the non-singularity of the metrization procedure. This transformation process ends with the creation of a machinery dedicated to the qualitative simulation of the concepts of solutions. The thesis ends with the study of practical cases.

The use of function has been recognized as an important part of the design process over last two decades, especially at the conceptual design stage, due to its critical role in determining the final product’s functionality. Although there are now some general methodologies dealing with functions or reasoning about functions, virtually no commercial CAD system can support conceptual design process due to their focus on geometrical modeling but not functional modeling. This paper presents a functional modeling approach to guide conceptual die design through functional reasoning steps including functional decomposition, functional supportive synthesis and function-structure mapping. The formed functional model provides a good basis to generate various die structures at the conceptual design stage, because function is a higher level of abstraction than structure, and helps to capture the designer’s intent. The functional modeling process has been implemented in a computerized design environment to expedite the conceptual die design process. / Singapore-MIT Alliance (SMA)

This thesis deals with the development of a Conceptual Design Tool for unmanned helicopters, so called VTOL UAVs. The goal of the Design Tool is: • Quick results • Good accuracy • Easy to use The two first points of the goal are actually more or less dependent on each other. In almost all cases a high accuracy gives a slow calculator and vice versa. In order to fulfill the goal a compromise between calculation accuracy and calculation time needs to be done. To make the Design Tool an easy to use program a graphical user interface is used. The graphical user interface allows the user to systematically work his way thru the program from a fictive mission to a complete design of a helicopter. The pre-requirements on the user have been eliminated to a minimum, but for the advanced user the possibilities to create more specific and complex helicopters are good. In order to develop a Conceptual Design Tool the entire helicopter needs to be seen as a complete system. To see the helicopter as a system all of the sub parts of a helicopter need to be studied. The sub parts will be compared against each other and some will be higher prioritized than other. The outline of this thesis is that it is possible to make a user friendly Conceptual Design Tool for VTOL UAVs. The design procedure in the Design Tool is relatively simple and the time from start to a complete concept is relatively short. It will also be shown that the calculation results have a good agreement with real world flight test data.

A conceptual design of a miniature vegetation cutter for use in minefields in southern Lebanon has been developed and the authors have evaluated its mechanical properties focusing on the stress in welded joints using the CAD software Pro/Engineer Wildfire 4.0. The conceptual design has been developed in the field in close cooperation with field staff from MAG Lebanon. The requirements from the field specify that the cutter should have a cutting range of 80 cm, be equipped with adjustable covers, weigh less than 200 kg, be fitted to a commercial hydraulic excavator, and have the ability to cut vegetation, bushes and small trees including (olive) trees with a diameter up to 10 cm. The miniature cutter is to be manufactured in the field and fitted to a commercial hydraulic ex­cava­tor (Caterpillar 301.6C). It consists of a rotor on which eight cutting blades, alternatively chains, are attached in a helix formation. The cutter is protected by adjustable covers. When in operation, the rotor spins at 750 revolutions per minute whereby the blades cut through the shrubs and bushes in the cutter’s path. The blades are mounted in a T-shape on arms, which are fastened to the rotor by a pin joint between two brackets (each) on the rotor. Blades and arms are to be welded together, as are the brackets to the rotor. These welded joints are the primary focus of the report. 3D CAD models have been created and analysed in PTC Pro/Engineer Wildfire 4.0 to ascertain that the stress in the joints will not exceed the yield strength of the weld consumables, which should be 500 MPa. Ideally, the stress in the joints would be half the yield strength. Type of bearings and a hydraulic motor have been selected for the cutter. Based on the specifica­tions of the hydraulic motor an approximation of the forces acting on the weld joints in the case of an accidental stop (e.g. collision with a rock) has been calculated, and entered into the CAD software. Also, an approximation of the size (diameter) of branches the cutter would be able to tear apart in the case of branches getting stuck has been calculated and shown to be about 14.6 mm. Based on this, it is estimated that the cutter should be used only in areas where the shrubbery is of 20-30 mm in diameter, maximum. Considering this, and the relative light weight of the cutter, it is not likely that the cutter will be able to cut through the larger olive trees as requested, but it is considered that the tool still could be a valuable asset for mine clearing in Lebanon. In order to cut through thicker trees, it would be necessary to increase the power supply to the cutting system as well as the sturdiness of the cutting parts. Finding the required power and technical solutions for this demands further research which does not fit within the time frame for this report. A preliminary weight approximation shows that the cutter will weigh roughly 170 kg, which falls below the limit of 200 kg and leaving some room for the bearings to be added. The results from the stress analyses show that the stress in the welded joints falls well below the yield limit of 500 MPa, but not below 250 MPa. Still, the stress in all the welded joints is shown to be less than 300 MPa or at 40 % of the limit, which may still be acceptable. The end user will have to decide whether this is an acceptable safety margin before manufacturing the cutter and if it is not, measures will need to be taken to reinforce the weld joints and try to minimise the stress concentration in them.

Aircraft conceptual design, as the first design stage, provides major opportunity to compress design cycle time and is the cheapest place for making design changes. However, traditional aircraft conceptual design programs, which are monolithic programs, cannot provide satisfactory functionality to meet new design requirements due to the lack of domain flexibility and analysis scalability. Therefore, we are in need of the next generation aircraft conceptual design environment (NextADE). To build the NextADE, the framework and the data management problem are two major problems that need to be addressed at the forefront. Solving these two problems, particularly the data management problem, is the focus of this research. In this dissertation, a distributed object-oriented framework is firstly formulated and tested for the NextADE. In order to improve interoperability and simplify the integration of heterogeneous application tools, data management is one of the major problems that need to be tackled. To solve this problem, taking into account the characteristics of aircraft conceptual design data, a robust, extensible object-oriented data model is then proposed according to the distributed object-oriented framework. By overcoming the shortcomings of the traditional approach of modeling aircraft conceptual design data, this data model makes it possible to capture specific detailed information of aircraft conceptual design without sacrificing generality. Based upon this data model, a prototype of the data management system, which is one of the fundamental building blocks of the NextADE, is implemented utilizing the state of the art information technologies. Using a general-purpose integration software package to demonstrate the efficacy of the proposed framework and the data management system, the NextADE is initially implemented by integrating the prototype of the data management system with other building blocks of the design environment. As experiments, two case studies are conducted in the integrated design environments. One is based upon a simplified conceptual design of a notional conventional aircraft; the other is a simplified conceptual design of an unconventional aircraft. As a result of the experiments, the proposed framework and the data management approach are shown to be feasible solutions to the research problems.